Recombinant Macaca fascicularis P2Y purinoceptor 13 (P2RY13)

What is the functional significance of P2Y13 receptor in Macaca fascicularis neural tissue?

P2Y13 receptors in Macaca fascicularis demonstrate significant involvement in metabolic regulation and neuroinflammatory processes. Research has revealed altered expression patterns of NF-κB-associated transcripts in oxytocin neurons of the paraventricular hypothalamus (PVHOXT) in obese and diabetic cynomolgus monkeys (Macaca fascicularis) . This suggests that P2Y13 may function as a direct downstream target of the NF-κB pathway in primates under metabolic stress conditions. The receptor appears evolutionarily conserved but exhibits context-dependent expression patterns that vary with metabolic status. Methodologically, researchers investigating P2Y13 function in macaque neural tissue should consider isolating specific neuronal populations through FACS sorting followed by transcript analysis to accurately characterize expression patterns across different metabolic conditions.

How does P2Y13 receptor expression in Macaca fascicularis compare to human and rodent models?

Significant species-specific differences exist in P2Y13 receptor pharmacology and expression patterns. Meta-analysis data reveals that human P2Y13 demonstrates higher sensitivity to ADP and ADP-like agonists (EC50 of 7.4 nM, 95% CI: 2.9–18.8) compared to rodent P2Y13 (EC50 of 149.8 nM, 95% CI: 64.3–348.8) . In Macaca fascicularis, P2Y13 expression patterns show similarities to human tissues, particularly in the context of metabolic disorders like diabetes mellitus, where both species exhibit altered expression in hypothalamic neurons . When designing cross-species research protocols, investigators should account for these potency differences when selecting appropriate agonist concentrations. Additionally, tissue-specific expression profiles vary significantly, with P2Y13-mediated responses in brain tissue showing greater sensitivity (EC50 of 0.3 μM, 95% CI: 0.02–4.89) compared to blood tissue (EC50 of 17.9 μM, 95% CI: 0.8–426) .

What methodologies are recommended for isolating and characterizing recombinant P2Y13 from Macaca fascicularis?

For successful isolation and characterization of recombinant Macaca fascicularis P2Y13, researchers should employ a multi-step approach. Begin by extracting RNA from relevant tissue samples (preferably brain regions with high P2Y13 expression) followed by RT-PCR amplification of the P2ry13 cDNA. For recombinant expression, subcloning into appropriate vectors such as pCDH-EF1-copGFP-T2A-Puro (at EcoRI and BamHI restriction sites) has proven effective . The resulting construct should be packaged into lentiviral vectors for subsequent transduction into target cells. Expression verification can be performed through qRT-PCR and FACS sorting for further purification. For functional characterization, patch-clamp electrophysiology to measure THIK-1 K+ currents provides valuable insights into receptor activity . Researchers should maintain cell cultures in DMEM containing 10% fetal bovine serum, 100 U/ml penicillin, and 100 U/ml streptomycin at 37°C with 5% CO2, with medium replacement every 1-2 days depending on cell conditions .

What are the primary agonists for P2Y13 receptors and their relative potencies?

P2Y13 receptors respond to a variety of purinergic agonists with significant differences in potency. The following table summarizes the relative potencies based on meta-analysis data:

How does P2Y13 receptor function differ from the closely related P2Y12 receptor in microglial cells?

The P2Y13 receptor plays a role distinctly different from its close relative P2Y12 in regulating microglial morphology and function. P2Y13 knockout studies reveal that microglia lacking this receptor exhibit less ramified morphology and reduced brain surveillance capability. Interestingly, P2Y13 knockout results in an increased P2Y12-mediated THIK-1 current, suggesting compensatory mechanisms . Despite this increased current, the directed motility toward ADP sources or brain injury sites is slower in P2Y13 KO mice due to their shorter processes requiring more time to reach targets. A striking difference is that baseline interleukin-1β release increases fivefold in P2Y13 KO models, while P2Y12 blockade in brain slices from these models does not affect surveillance . This indicates that P2Y13-deficient microglia exist in a unique state neither typically nonactivated nor fully activated but in an intermediary "primed-like" phenotype. For experimental designs investigating microglial purinergic signaling, researchers should consider the complex interplay between these receptors rather than studying them in isolation.

What are the methodological considerations for investigating P2Y13 receptor involvement in metabolic regulation in Macaca fascicularis models?

When investigating P2Y13 receptor involvement in metabolic regulation using Macaca fascicularis models, researchers should implement a comprehensive approach. First, establish appropriate metabolic stress conditions through high-fat diet (HFD) feeding or diabetes induction protocols while monitoring physiological parameters. For tissue analysis, prepare brain slices (300-350 μm) from the paraventricular hypothalamus using vibratome sectioning in specialized slicing solution (92 mM NaCl, 20 mM HEPES, 30 mM NaHCO3, 2.5 mM KCl, 2 mM CaCl2, 1 mM MgCl2, 1.2 mM NaH2PO4, 25 mM glucose, 1 mM kynurenic acid, 5 mM Na-ascorbate, 3 mM Na-pyruvate, pH 7.4) . Critical methodological considerations include: (1) immediate transfer of slices to warmed solution (33-35°C) for 15 minutes before transferring to recovery solution at room temperature; (2) removal of kynurenic acid from experimental solutions to avoid blocking glutamate receptors; and (3) focusing on 2-4 month old subjects when P2Y13 mRNA expression is relatively high . For mechanistic studies, consider lentiviral-mediated overexpression or silencing of P2Y13 in specific hypothalamic nuclei, followed by comprehensive metabolic phenotyping including food intake measurements, glucose tolerance tests, and insulin sensitivity assessments .

How can researchers effectively differentiate between direct P2Y13 effects and compensatory changes in P2Y12 signaling in experimental models?

Differentiating between direct P2Y13 effects and compensatory P2Y12 signaling changes requires sophisticated experimental approaches. First, implement conditional and cell-type specific knockout models rather than global knockouts to minimize systemic compensatory effects. Use pharmacological tools with selectivity verification—testing P2Y13 antagonists on P2Y13 knockout tissues to confirm specificity. A dual-intervention approach combining genetic manipulation with selective pharmacological agents provides the most robust strategy. Specifically, researchers should: (1) compare P2Y13 knockouts with wild-type animals treated with selective P2Y13 antagonists; (2) perform complementary experiments using P2Y12 antagonists in P2Y13 knockout tissues to isolate compensatory mechanisms; and (3) conduct time-course studies to distinguish between acute and chronic compensatory responses . Advanced electrophysiological approaches measuring THIK-1 K+ currents in response to various purinergic agonists can further differentiate receptor-specific responses. Additionally, measuring microglial surveillance and motility parameters through time-lapse imaging in the presence of selective antagonists for each receptor provides functional readouts of receptor-specific activity .

What are the technical challenges in analyzing P2Y13 receptor expression in different cell types within the Macaca fascicularis brain?

Analyzing P2Y13 receptor expression across different cell types in the Macaca fascicularis brain presents several technical challenges requiring specialized approaches. The first challenge involves P2Y13's potentially low protein expression despite adequate mRNA levels, possibly due to constitutive ubiquitination and proteasomal degradation . To address this, researchers should employ multiple detection methods including RNAscope fluorescence in situ hybridization for mRNA detection alongside immunohistochemistry with validated antibodies for protein detection. For cell-type specificity analysis, implement fluorescence-activated cell sorting (FACS) of dissociated brain tissues followed by qRT-PCR analysis. This approach was successfully used to isolate PVHOXT neurons from HFD-fed mice, revealing drastic upregulation of P2ry12 transcripts . Additionally, researchers should be aware that P2Y13 expression changes dynamically under pathological conditions such as demyelination and neuropathic pain , necessitating careful experimental timing and multiple time-point analyses. For optimal results, tissue preparation should follow protocols validated for primate brain samples, with particular attention to fixation conditions and antigen retrieval steps that preserve purinergic receptor epitopes.

How can RNA-sequencing approaches be optimized to study P2Y13-mediated gene expression changes in Macaca fascicularis neural stem cells?

Optimizing RNA-sequencing approaches for studying P2Y13-mediated gene expression changes in Macaca fascicularis neural stem cells requires careful consideration of several methodological aspects. Based on successful studies in other models, researchers should begin by isolating specific cell populations through FACS sorting of GFP-labeled cells transduced with either control vectors or P2Y13-overexpressing constructs . For neural stem cell isolation from the subependymal zone (SEZ), dissect tissue samples 7 days post-injection of lentiviral constructs to capture early transcriptional changes. RNA extraction protocols should be optimized for low-input samples, potentially using methods like Smart-seq2 for high-quality full-length cDNA amplification from limited material. Principal component analysis (PCA) should be employed to verify sample clustering and experimental reproducibility . Analysis pipelines should include differential expression analysis comparing P2Y13-overexpressing cells with controls, followed by pathway enrichment analysis to identify biological processes affected by P2Y13 signaling. Previous studies identified 1,432 upregulated and 59 downregulated genes in P2Y13-overexpressing neural lineage cells , providing valuable reference data for validating experimental outcomes. Special attention should be given to genes associated with activation, quiescence, and lineage progression to understand how P2Y13 influences neural stem cell behavior.

What are the optimal conditions for achieving successful overexpression of P2Y13 in Macaca fascicularis cell cultures?

Achieving optimal overexpression of P2Y13 in Macaca fascicularis cell cultures requires precise control of multiple experimental parameters. Based on successful protocols, researchers should clone the full-length Macaca fascicularis P2ry13 cDNA into a lentiviral expression vector such as pCDH-EF1-copGFP-T2A-Puro at EcoRI and BamHI restriction sites . This construct pairs P2Y13 expression with a fluorescent reporter (GFP) for visualization and a puromycin resistance gene for selection. For viral packaging, use a third-generation lentiviral system with reduced cytotoxicity in primate cells. Transduce target cells at a multiplicity of infection (MOI) between 5-10 for optimal expression without cytotoxicity. Following transduction, implement a 72-hour expression period before performing FACS sorting to isolate successfully transduced cells . Culture cells in DMEM supplemented with 10% fetal bovine serum, 100 U/ml penicillin, and 100 U/ml streptomycin at 37°C with 5% CO2 . For stable expression, maintain puromycin selection (concentration determined by kill curve analysis) and verify expression through qRT-PCR and Western blot analysis. To enhance expression levels, consider codon optimization of the P2ry13 sequence for Macaca fascicularis and inclusion of a Kozak consensus sequence before the start codon to improve translation efficiency.

How should researchers design experiments to investigate the role of P2Y13 receptors in neuroinflammatory processes in Macaca fascicularis models?

Designing experiments to investigate P2Y13 receptors in neuroinflammatory processes in Macaca fascicularis models requires a multi-faceted approach. First, establish appropriate inflammatory stimuli relevant to the research question—options include lipopolysaccharide (LPS) administration, sterile injury models, or metabolic stressors such as high-fat diet feeding that has been shown to alter purinergic signaling in the hypothalamus . Include multiple experimental groups: (1) control animals, (2) animals with inflammatory stimuli alone, (3) animals with P2Y13 receptor modulation alone, and (4) animals with both inflammatory stimuli and P2Y13 modulation. For P2Y13 modulation, consider both pharmacological approaches using selective agonists/antagonists and genetic approaches using viral-mediated overexpression or knockdown. Assessment parameters should include: (1) microglial morphology analysis through immunohistochemistry and 3D reconstruction, (2) surveillance behavior through in vivo two-photon imaging if possible, (3) cytokine profiling with particular attention to interleukin-1β levels which show fivefold increases in P2Y13 KO conditions , and (4) functional outcomes relevant to the specific research question. Include time-course analyses to distinguish between acute and chronic effects, and consider implementing cell-type specific approaches to isolate neuronal versus glial P2Y13 contributions to the inflammatory response.

What methodological approaches should be used to study P2Y13-mediated effects on neural stem cell behavior in Macaca fascicularis?

To study P2Y13-mediated effects on neural stem cell behavior in Macaca fascicularis, researchers should implement a comprehensive methodological framework based on successful studies in other models. Begin with stereotaxic injections of lentiviral vectors for either P2Y13 overexpression (LV-P2Y13-IRES-GFP) or control vectors (LV-GFP) into the subependymal zone (SEZ) neurogenic niche . For tracking neural stem cell activation and lineage progression, analyze the relative proportion of GFP-positive cells in the rostral migratory stream (RMS) versus those remaining in the ventral wall of the SEZ at specific timepoints post-injection (e.g., 14 days) . Quantify GFP+/GFAP+/SOX2+ neural stem cells to assess quiescence/activation balance. For mechanistic insights, perform RNA-sequencing on FACS-sorted GFP+ cells isolated 7 days post-injection to identify gene expression changes associated with P2Y13 activity . Functional assays should include proliferation analysis through EdU incorporation, differentiation potential assessment through immunostaining for lineage-specific markers, and electrophysiological characterization of neural stem cell responses to P2Y13 agonists. For in vitro validation, establish primary neural stem cell cultures from Macaca fascicularis SEZ and manipulate P2Y13 expression/activity while monitoring functional outcomes including proliferation rates, mode of division (symmetric vs. asymmetric), and differentiation potential.

How relevant are findings from Macaca fascicularis P2Y13 studies to understanding human neurological and metabolic disorders?

Findings from Macaca fascicularis P2Y13 studies offer considerable translational value for understanding human neurological and metabolic disorders due to several factors. Phylogenetically, cynomolgus macaques represent one of the closest experimental models to humans, with significant genetic and physiological similarities. Research demonstrates comparable patterns of P2Y13 receptor expression changes in metabolic disorders between humans and Macaca fascicularis, particularly in the context of diabetes mellitus . Both species exhibit similar "ectopic" expression of P2Y receptors on oxytocin neurons in the paraventricular hypothalamus under metabolic stress conditions . Pharmacologically, human P2Y13 receptors demonstrate higher sensitivity to ADP and ADP-like agonists compared to rodent models, with EC50 values of 7.4 nM (95% CI: 2.9–18.8) versus 149.8 nM (95% CI: 64.3–348.8) for rodents . This translational relevance extends to potential therapeutic applications, as neuronal expression of P2Y12 (another purinergic receptor) accompanied by elevation of ATP in the hypothalamus constitutes a novel purinergic pathway in the metabolically stressed hypothalamus that can be targeted pharmacologically . When designing translational studies, researchers should prioritize Macaca fascicularis models over rodent models particularly for pharmacological interventions targeting the P2Y13 receptor, as dosing predictions based on non-human primate data will likely translate more accurately to human applications.

What are the key considerations when extrapolating P2Y13 receptor pharmacology from Macaca fascicularis models to potential human therapeutic applications?

When extrapolating P2Y13 receptor pharmacology from Macaca fascicularis to human applications, researchers must address several critical considerations. First, acknowledge species-specific pharmacological differences—meta-analysis data indicates that human P2Y13 demonstrates approximately 20-fold higher sensitivity to ADP-like agonists compared to rodent receptors , and while Macaca fascicularis P2Y13 pharmacology shows greater similarity to human receptors, precise species differences should be characterized through comparative dose-response studies. Second, consider tissue-specific differences in receptor sensitivity, as brain P2Y13 receptors demonstrate significantly higher sensitivity (EC50 of 0.3 μM, 95% CI: 0.02–4.89) compared to those in blood (EC50 of 17.9 μM, 95% CI: 0.8–426) . This has implications for drug delivery strategies and potential off-target effects in different tissues. Third, account for context-dependent receptor expression patterns, as P2Y13 expression changes dynamically under pathological conditions like demyelination, neuropathic pain, and metabolic stress . Drug development should consider how these altered expression patterns might affect therapeutic efficacy in different disease states. Finally, implement allometric scaling principles when extrapolating dosing from macaque studies to human applications, considering factors like differences in receptor density, metabolic clearance, and blood-brain barrier permeability. For central nervous system applications, evaluate whether nasal administration routes effective in preclinical models would translate successfully to human patients .